Sumidero Canyon

Sumidero Canyon cuts through Chiapas, Mexico, near the town of Chiapa de Corzo, running about 13 kilometers long with walls between 200 and 700 meters high, reaching a maximum of 1,000 meters, and narrowing to 1 to 2 kilometers wide. Its walls expose layers of Upper Mesozoic limestone containing fossils of ancient marine creatures, evidence that the rock formed on a sea floor long before the canyon existed. The canyon itself began forming about 35 million years ago, roughly contemporary with the Grand Canyon, opened by cracks in the Earth's crust and then carved deeper by erosion from the Grijalva River, which flows through it from south to north with an average flow of about forty million cubic meters and bends as sharply as 90 degrees in places. The canyon also holds seasonal streams, underground water movement, caves and karst formations shaped by the same limestone geology. This entity documents Sumidero Canyon specifically as a geological formation, a limestone gorge opened by crustal fracturing and deepened over 35 million years by the Grijalva River.